Outside the University of Maryland’s basketball arena, about 2,000 people were lined up by 6:30 a.m. Friday, camped out with foldable chairs, blankets, decks of cards and caffeine.

Those at the front of the line had been there since 10 p.m. Thursday. If they had been wearing Terrapins red, it would have looked like die-hard fans were waiting to attend a big game. Instead, the crowd was gathered for root canals, cavity fillings, tooth extractions and cleanings.

The university and Catholic Charities have transformed the basketball court at the Xfinity Center in College Park into a makeshift dental clinic that will operate through Saturday. One hundred dental chairs were organized in neat rows under the arena lights and banners as health practitioners dressed in pale blue disposable gowns provided free dental care for underserved Maryland residents.

But the crowd was such that, despite all the good intentions, not everyone’s needs could be met by the end of the day.

Linda Frazier, 64, was turned away from last year’s event at St. Vincent Pallotti High School in Laurel, so she made sure to arrive early. After showing up at 3:30 a.m., she received a bright-orange wristband with 269 written in black marker.

Laid off two years ago, Frazier said dental care has become a pricey burden. Instead of going to the dentist, she watches closely for free clinics such as this one.

“It’s like we take dental for granted when we’re working, but, hey, when it’s gone, it’s gone,” she said.

She clutched her chin. “Something feels loose,” she said.

Since 2007, when 12-year-old Deamonte Driver died from an easily preventable dental infection, many changes have taken place statewide to make dental care more available. The Affordable Care Act covers dental care for children and pregnant women, but many adults still do not have regular access to care because they are uninsured or cannot afford full dental insurance or co-payment plans.

Even with insurance, sometimes the expenses for the necessary procedures can be too high. As a result, almost 20 percent of Maryland residents had not visited a dentist in the past five years, according to a 2012 state health department survey.

As the doors opened at 7 a.m., Deacon Jim Nalls of Catholic Charities called out numbers over the microphone as those waiting their turn sat in the red plastic stadium chairs.

In his second year of being involved in the large-scale free dental care event, Nalls said he still saw a huge need.

Patients lined up in rows of dental chairs were served with an almost assembly line efficiency. (Michael S. Williamson/The Washington Post)

“We’re doing the best we can,” Nall said. “[Oral health] is basic. If you can’t eat, it’s hard to be healthy. There’s nothing for adults if you can’t find the money to pay for it.”

Organizers of the Mid-Maryland Mission of Mercy and Health Equity Festival had worked to increase the event’s capacity to 1,200 from last year, when they had served roughly 700 but had to turn away 300 people, he said. But although volunteers had managed to serve more than 750 people by the end of the day Friday, they had to turn away 1,000, inviting them to try again Saturday.

The clinic was also sponsored by the Maryland Department of Health and Mental Hygiene, the Maryland State Dental Association and corporate partners.

Geneva Taylor, 29, of Silver Spring works as a caretaker and does not have insurance. A few months ago, she had to rush to a dentist’s office for an emergency extraction because of an infection. Her mother paid the bill, she said, recalling the charge exactly: $768. Taylor did not want to rely on her mother’s generosity again and was hoping to receive a root canal, an extraction and a cleaning.

“I just remembered I hate the dentist,” she said. She joked about the strange setting as she sat in the stands. “I feel like doing the wave [dance], the toothless wave.”

William Goettling, 29, and his twin brother, Charles, were also hoping to receive root canals. Examining a picture he had taken of his teeth that showed blackened craters in his back molars, Goettling said he was told at a consultation that it would take an estimated $14,000 for the procedures he needed.

“I brush my teeth really long and hard, but I used to drink energy drinks three times a day,” he said.

The pain wasn’t unmanageable, so he wouldn’t have treated it if it weren’t free, he added.

Around 10 a.m. the news spread that root canals would no longer be provided because the few specialists were already too backed up. Taylor, who was among the first to line up, was told that perhaps they could record her name and put her at the top of the list for Saturday.

Stanley Cohen, a dentist who practices in Olney, examined X-rays and helped patients choose just two procedures from a menu of treatments. When patients asked for a root canal, he found himself saying “no” and suggesting they consider an extraction instead.

“It’s tough,” he said. “It didn’t hit me until I saw the lines this morning how great it is to be here.”

Friday was the first time in 50 years that Allen Howard, 78, had seen a dentist.

“I had one that was hurting real bad in the back, and that was the first one to go,” he said.

Eight extractions later, he exited the stadium, a small smile evident despite a mouth full of gauze.